Saw blade for a frame saw having teeth with reinforced edges

ABSTRACT

A saw blade for a frame or gang saw has teeth each formed with a reinforced edge region. This region has a planar upper surface inclined rearwardly and inwardly away from a cutting direction and a pair of planar flank surfaces converging backwardly in the cutting direction and each defining a locus of lines perpendicular to the cutting direction whereby the lateral flanks include angles of at least 90* with the upper surface and preferably are perpendicular thereto.

llited States Patent Kulik et al.

SAW BLADE FOR A FRAME SAW HAVING TEETH WITH REINFORCED EDGES Inventors:Leo Kulik; Gustav Gustenau, be

of Wien 10, Austria v Assigleei 110 If?! UPDY EKX fiu.Maschinen-messerfabrik, Wein, Austria Filed: Jan. 13, 1971 Appl. No.:106,014

Foreign Application Priority Data Jan. 14, 1970 Austria ..A 346/70 us.'01 83/835, 30/388 Int. Cl. ..B27b 33/04 Field of Search...143/133 A,133 B, 133 R, 140, 143/141, 142, 143, 133; 29/95 B, 95

[ 1 Jan. 23, 1973 [56] References Cited UNITED STATES PATENTS 1,690,80311/1928 Vanderwee ..143/l33 A 3,048,207 8/1962 Ferrari ..l43/133 B431,510 7/1890 Douglas ..l43/l40 Primary ExaminerDonald R. SchranAttorney-Karl F. Ross [57] ABSTRACT A saw blade for a frame or gang sawhas teeth each formed with a reinforced edge region. This region has aplanar upper surface inclined rearwardly and inwardly away from acutting direction and a pair of planar flank surfaces convergingbackwardly in the cutting direction and each defining a locus of linesperpendicular to the cutting direction whereby the lateral flanksinclude angles of at least 90 with the upper surface and preferably areperpendicular thereto.

5 Claims, 4 Drawing Figures SAW BLADE FOR A FRAME SAW HAVING TEETH WITHREINFORCED EDGES FIELD OF THE INVENTION The present invention relates toa saw blade usable in a frame saw. More specifically this inventionconcerns a blade of this type having teeth formed with thickened edgeregions.

BACKGROUND OF THE INVENTION It has been found advantageous to thickenthe upper edges of the teeth of frame-saw blades, that is to make theteeth thicker along the outside, wood-contacting edge than inwardlytherefrom. This is generally done by stamping which imparts a thickenededge region having flank surfaces which are continuous with and divergeoutwardly from the side faces of the blade, and hence include angleswith the trailing surface or top of the tooth which are less than 90.Such a thickened edge imparts great strength to the tooth and allows itto be reground many times for a long blade-service life. Springlikedeformation of the tooth back in the direction of cutting is almostcompletely eliminated by the reinforced edge.

With a blade so formed the leading edge of the top surface of the toothis also the cutting edge, and since the two flanks of the thickened edgetaper inwardly away from this cutting edge, the corners of the leadingedge alone serve to guide the saw in the kerf or cut. For this reasonthe kerf formed by such a blade is often irregular, the guiding meansbeing limited to two points of contact with the kerf.

OBJECTS OF THE INVENTION It is an object of the present invention toprovide an improved saw blade of the above-mentioned type, i.e. forframe or gang saws.

Another object is to provide such a blade which overcomes theabove-given disadvantages.

Yet another object is to provide a tooth structure for a saw blade whichhas long service life, guides itself in the kerf, and which can bereground many times before being discarded.

SUMMARY OF THE INVENTION The above objects are obtained by a saw bladehaving a plurality of teeth in the plane of the blade body each formedwith a thickened edge region (i.e. a prismatic formation projectinglaterally of the thinner planar blade body and joining the latterpreferably at right-angle shoulders) which has an upper surface inclinedoutwardly away from the blade body in a forward cutting direction and apair of flank surfaces converging rearwardly and inwardly toward theblade body and each defining a locus. of parallel lines substantiallyperpendicular to the forward-cutting direction. In other words, thelateral flanks of the tooth are offset outwardly from the blade bodysymmetrically on opposite sides of a median plane through the blade andinclude angles of at least 90 with the aforementioned upper surface.

In accordance with a feature of this invention, the two flank surfacesand the upper surface are all planar with the convergent planes of theflanks lying at right angles to the plane of the upper surface.

The thickened edge region therefore presents three cutting edges insteadof the customary one, since the leading edges of the two flanks in sucha blade also serve to cut. This alone greatly reduces wear of the blade.At the same time these lateral cutting edges formed by the leading(relative to the forward cutting direction) edges of the flank surfacesserve to guide the blade in the kerf with line contact with the sides ofthe kerf, thereby eliminating vibration and irregular cutting, and millthe sides of the cut to leave the cut surface relatively smooth.

DESCRIPTION OF THE DRAWING The above and other objects, features, andadvantages will become apparent from the following description,reference being made to the accompanying drawing, in which:

FIG. 1 is a side view of a portion ofa blade according to the presentinvention;

FIG. 2 is a top view of the blade portion shown in FIG. 1; and

FIGS. 3 and 4 are sectional views corresponding to cuts taken alonglines III III and IV IV, respectively, of FIG. 1, FIG. 4 illustratinganother embodiment of the invention.

SPECIFIC DESCRIPTION As shown in FIGS. 1 5, a gangor frame-saw blade 1is provided with a plurality of teeth 7 adapted to cut in the directionindicated by arrow 5 (forward direction). Each tooth 7 is formed on theblade body 1a with a thin web lb of the thickness of the blade body andis provided with an upper reinforced edge region 2 having an uppersurface 8 inclined down rearwardly in the direction 5 and a pair offlank surfaces 3 converging rearwardly in that direction.

Each side or flank surface 3 lies in a plane P which defines a locus oflines parallel to the plane P of symmetry of the blade 1, the latterplane lying parallel to the direction of cut 5. The blade 1 thus has aplane P in line with the cut direction 5. In this example the planes Pand P include angles a of 2 to 20 preferably about 10 with one anotherand the planes P are arranged symmetrically to each side of the plane P.

The upper surface 8 is planar and defines a surface P which is inclinedat an angle B of 15 to 45, preferably about 25 to a plane P of thecrests of the teeth parallel to the direction 5 and perpendicular toplane P and forms, with the tooth leading face 11, a cutting edge 9. Theface 11 lies in a plane P at an angle. of 50 to 80, preferably about tothe direction 5 and plane P' so that the angle of cutting edge 9 isbetween 35 and 55, preferably about 45.

The thickened region 2 is generally prismatic and can be of rectangularcross-section or even of trapezoided section with the narrow baseforming the surface 8, and extends along substantially all the upperregion 10 of the tooth 7, allowing this tooth to be ground backpractically its whole length for reuse. In this case the length of theregion 2 is originally equal to about two-thirds of the distance on theblade from point 9 to point 9.

The region 2 is advantageously formed by hard or cold stamping andmachined and then hardened (casehardened) on its surfaces 3 and 8, alongits full length 10 so that as it is reground it retains the requisitecutting hardness. A hard-chrome coating 6 is shown in FIG. 3 coveringthe top and sides of the region 2.

FIG. 4 shows, however, how the region 2 can be constituted by a hardmaterial which is brazed onto or set into the blade 1. Ideally, anelongated substantially parallelopipedal chip of carbide or a similarhighly wear-resistant material is used, giving the blade excel lent wearresistance and long-lasting sharpness. The chip or body of carbide is ofsquare cross section and unitarily bonded to the tooth 7.

It is worth noting that, due to the inclination at of the edge 2 and thelength of this edge, the rear end lies inwardly of the leading edge. Inthis manner, the whole side surface 8 on each side serves to sweep thecut, making sawdust elimination rapid.

FIG. 3 also shows that the leading edges 4 of the side surfaces 8 arealmost completely parallel to the plane P, for best guiding of the blade1 in the kerf.

We claim:

1. A saw blade for a frame saw comprising a planar blade bodyprovidedwith a multiplicity of spaced apart teeth forwardly overhangingteeth-spacing recesses in the direction of cutting movement of theblade, and respective elongated reinforcement portions extending allalong the crests of each of said teeth of a thickness in excess of thethickness of said body and disposed symmetrically with respect to thefaces thereof, each of said reinforcement portions comprising:

a front planar flank inclined rearwardly away from an apex of thereinforcement portion and at an acute angle to a plane perpendicular tosaid body and said direction of cutting movement;

a planar top flank defining an acute angle with said front flank at saidapex and inclined rearwardly at an acute angle away from a planeparallel to said cutting direction but perpendicular to said body; and

a pair of longitudinally extending planar lateral flanks of uniformwidth over the entire length of the reinforcement portion and definingsharp edges at angles of with said top flank, said lateral flanksconverging toward one another symmetrically rearwardly and each having alimiting edge spaced from the edge defined with said top flank andparallel thereto.

2. The blade defined in claim 1 wherein said flanks are hardened.

3. The blade defined in claim 1 wherein said flanks are coated with ahighly wear-resistant material.

4. The blade defined in claim 1 wherein said reinforcement portion isformed by a body of highly wearresistant material unitarily bonded tosaid tooth.

5. The blade defined in claim 4 wherein said body is substantiallysquare in cross section.

1. A saw blade for a frame saw comprising a planar blade body providedwith a multiplicity of spaced apart teeth forwardly overhangingteeth-spacing recesses in the direction of cutting movement of theblade, and respective elongated reinforcement portions extending allalong the crests of each of said teeth of a thickness in excess of thethickness of said body and disposed symmetrically with respect to thefaces thereof, each of said reinforcement portions comprising: a frontplanar flank inclined rearwardly away from an apex of the reinforcementportion and at an acute angle to a plane perpendicular to said body andsaid direction of cutting movement; a planar top flank defining an acuteangle with said front flank at said apex and inclined rearwardly at anacute angle away from a plane parallel to said cutting direction butperpendicular to said body; and a pair of longitudinally extendingplanar lateral flanks of uniform width over the entire length of thereinforcement portion and defining sharp edges at angles of 90* withsaid top flank, said lateral flanks converging toward one anothersymmetrically rearwardly and each having a limiting edge spaced from theedge defined with said top flank and parallel thereto.
 2. The bladedefined in claim 1 wherein said flanks are hardened.
 3. The bladedefined in claim 1 wherein said flanks are coated with a highlywear-resistant material.
 4. The blade defined in claim 1 wherein saidreinforcement portion is formed by a body of highly wear-resistantmaterial unitarily bonded to said tooth.
 5. The blade defined in claim 4wherein said body is substantially square in cross section.